add hover filter

Author: betich

index.html

@@ -44,6 +44,10 @@
         background-size: cover;
         background-repeat: none;
         background-position: center;
+        transition: filter 200ms ease;
+      }
+      .event:hover {
+        filter: brightness(0.75);
       }
       .event > a {
         position: absolute;